Speaker
Description
The rare-earth isotopic chain of Samarium provides an excellent opportunity to systematically investigate the evolution of nuclear structure effects from the near-spherical ($β_{2}$=0.00) $^{144}$Sm isotope to the well-deformed system ($β_{2}$=0.27) $^{154}$Sm. As the nuclear shape changes, statistical properties such as the nuclear level density (NLD) and $\gamma$-strength function ($\gamma$SF) are expected to be affected. In particular resonance modes, such as the Pygmy Dipole (PDR), Scissors Resonances (SR), and the recently discovered Low-Energy Enhancement (LEE) in the rare-earth region may reveal interesting features when their evolution is investigated across several nuclei in an isotopic chain. An experiment was performed at Oslo Cyclotron Laboratory (OCL) where the NaI(Tl) $\gamma$-ray array and silicon particle telescopes were utilized to measure particle-$\gamma$ coincidence events from which the NLDs and $\gamma$SFs have been extracted below the neutron threshold, Sn, using the Oslo Method (A. Schiller et al., 2000). The deuteron beam was used to populate excited states in $^{153,155}$Sm through transfer reaction (d,p$\gamma$). Based on the results from these measurements, the extracted NLDs and $\gamma$SFs have been used to investigate the evolution of nuclear structure effects, in particular the SR, in $^{153,155}$Sm. In this talk, I will present results of statistical properties for $^{153,155}$Sm and compare them to previous measurements of $^{148,149}$Sm and $^{151-154}$Sm.
This work is based on the research supported in part by the National Research Foundation of South Africa (Grant Number 118846) and by the IAEA under Research Contract 20454.
